Protractor.



A. C. ERNEST.

FROTRACTOR.

APPLICATION man APR.|1.1914.

COLUMBIA PLANOURAPH C0.,\VASH1NGTON, D. c.

A. C. ERNEST.

PROTRACTOR.

APPLICATION FILED APR.17.1914.

Patented Nov. 9, 1915.

2 SHEETS-SHEET 2.

.aras ortica ALBERT C. ERNEST, OE I-IUBBARD, TEXAS, ASSIGNOR, BY DIRECTAND MESNE ASSIGN- MENTS, TOSTEVE C. WALLACE, OF COOLIDGE, TEXAS.

PROTRACTOR.

Specification of Letters Patent.

Patented Nov. 9, 1915.

Application filed-April 17, 1914. Serial N o. 832,551.

To aZZ whom it may concern.'

Be it known that I, ALBERT C. ERNEST,

citizen ofthe United States, residing at Hubbard, in the county of Hilland State of Texas, have invented certain new and useful Improvements inProtractors, of which the following is a specilication.

This invention relates to protractors and more particularly to aprotractor or gage for use by carpenters in cutting the rafters for abuilding roof, the aim of the invention Abeing to provide an instrumentof this class which will obviate the use of the ordinary carpenterssquare in obtaining the desired measurements and'in determining theangles at which the ends of the rafters are to be cut, and which willfurther obviate the necessity of a carpenter making calculations whichare necessary if the ordinary square is to be employed.

In the accompanying drawings: Figure 1 is a perspective view of theinstrument embodying the present invention. Fig. 2 is a plan view of oneside thereof. Fig. 8 is a similar view of the other side. Fig. 4 is anedge view of the instrument.

Corresponding and like parts are referred to in the followingdescription and indicated in all the views of the accompanying drawingsby the same reference characters.

The instrument comprises a stock consisting of spaced plates 1 which areof counterpart outline and which have parallel edges. The plates l arespaced apart at one end by means of a spacing strip 2 althoughl thestock may be cut from a single piece of material if desired. Theinstrument also includes a blade which is indicated by the numeral 3.The blade 3 is substantially triangular, its side edges indicated one bythe numeral 4; and the other by the numeral 5 extending at an angle of90degrees with respect to each other. The blade atthe'base of thetriangle, howevenis Vapproximately rectangular, this portion beingindicated by the numeral 6 and being of a width equal to the width ofthe stock l so that the blade may be positioned with its said portion 6housed between the plates comprisingthe stock. At one corner the bladeis pivotally mounted between the ends of the plates 1 opposite the endswhich are spaced by the strip 2 by means of a bolt or rivet 7 passedthrough the said ends of the plates l and through the said corner of theblade. It

will now be apparent that the blade may be adjusted angularly withrespect to the stock, and it is in fact contemplated that the bladeshall be so adjusted so as to bring certain scale marks on its facesinto registry with the edges of the plates comprising the stock wherebyto secure a certain definite angular adjustment of the blade withrespect to the stock, so that when the stock is disposed against thework to be out, the line of cut may be marked upon the work by running apencil along one or the other of the edges 4L and 5 of the blade.

The face of one of the plates l comprising the stock is divided byintersecting lines extending lengthwise and transversely of the saidface, into columns, at the upper end of each of which columns is markeda numeral indicating the width of the building in feet, these widthindications extending in numerical order in a series from the inner tothe outer end of the blade, as for example, the numerals il, G, 8, etc.,indicated at S in Fig. 2 of the drawings. At that end of the series ofcolumns next adjacent the inner end of the stock there is located acolumn 9, and in this column is arranged a series of indicationsdenoting the pitch of the roof to be constructed, as for example, 6x12,SX12,.etc. In each of the columns headed by the indications denoted bythe numeral 8 there is arranged a column of numerals indicating in feetand inches the lengths of the various common rafters. For example, atthe intersection of the column headed by the numeral 6 with thelongitudinally extending column at the end of which appears the pitchindicated 6x12, we find the numerals 3.4, which indicate that if thespan of the roof is to be 6 feet and the pitch is to be 6x12, the lengthof the common rafter will be 3 feet, 4f inches. The portion 6 of theblade?) at the corresponding side of the instrument is likewise dividedinto a number of columns, corresponding to the columns 8 previouslyreferred to and indicated here by the numeral 11, and into a column l2bearing at one end the word Spain this column having therein a number ofnumerals indicating the span of the roof. .In each of the columns 11 ofthe table now referred to is arranged a series of numerals designatingthe llengths of the Vdiierent hip rafters. For example, if the buildingis 10 feet wide and the pitch is 6x12, the length of the hip The othercolumns 13 are headed by numerals indicated at 15, denoting the span ofthe roof and in the spaces of these columns are numerals indicating infeet and inches the lengths of the different octagon hip rafters. Forexample, if the span is 8 feet and the pitch of the roof is 6x12 we findthat the octagon hip rafter will be 4 feet, 9 inches in length. Othercolumns 16 are also marked olf upon the said face of the blade andbetween the series of columns 13 and 16, or in other words, at the innerends of the series of columns 13 and 16, there is printed the legendLength of octagon jack, or some other appropriate heading to indicatethat the numerals in the columns 1.6 denote in feet and inches thelengths of the Octagon jack rafters.

Returning now to Fig. 2 of the drawings,

it will be observed that the first-mentioned face of the blade 3 isdivided into a number of columns extending parallel to the edge 4 of theblade, one of these columns being indicated by the numeral 17, anotherby the numeral 18, a third by the numeral 19 and a fourth by the numeral20. Within the columns 17, 18, 19 and 20 is marked a number of lines 21,22, 23 andy 24 respectively, these lines extending tangentially withrespect to a circle having the rivet 7 for its center and touching thebase line of the triangular portion of the blade, the said base line ofthis portion being indicated specifically by the numeral 25. The column17 is headed by a legend, such for example, as Pitch of common rafter,the column 18 is headed by a legend, such for example, as

Pitch of hip rafter, the column 19 by a legend, such for example, asSide cut of jack rafter, and the column 20 is headed by a legend, suchfor example, as Side cut of hip on ridge, and the lines 21, 22, 23, and24 in the said columns 17, 18, 19 and 20, are marked with numeralcombinations referring directly to the legends at the heads of theColumns. Adjacent the edge 4, the said face of the blade 3 bearslegends, as

for example Top cut of rafters and Backing of hips indicating that thisedge is to be employed in the marking of these cuts of the rafters, theblade having been of course previously adjusted so that the proper onesof the lines 21, 22, 23 and 24, as thev case may be, may register withthe edge, of the stock. In a like manner the blade bears a legendadjacent the edge 5 thereof, as Bottom cut of all'rafters, indicatingthat'a pencil or other marking instrunient is to be drawn along thisedge in mak- 'cctagon hip on ridge, Side cut of octagon jacks, Side cutfor polygon7 and"Miter cut for polygon, and the several columns aredivided by a number of radially extending lines 31, 32, 33, 34 and 35respectively,

these several lines being marked with designations bearing relation'tothe several legends as will be readily understood. The other side of theblade 3 is preferably provided with a scale 36, the scale marks of whichare indicated by numerals denoting the angular relation of the edges 4and 5, as the case may be, to the stock at various angular adjustmentsof the blade upon its pvot 7, so that the instrument may be employedlalso as a bevel gageor for ing the angle of any bevel cut.`Furthermore, the said face of the blade adjacent the edge 5 ispreferably marked with a legend,

determin- A as for example, Make all side cuts here,

and adjacent its edge 4 With a legend, such for example, as Top cut ofrafter, Polygon gage cut here. It will be understood of course thatwhile the arrangementof the scales herein shown is the preferredarrangement, the same may be-varied within the termsV of the appendedclaim without departing from the spirit of the invention.

lllhile, as before stated, the pivot-7 may Y be in the form of a bolt ora rivet, it is pref- V erable that it be a bolt and provided with athumb nut 7u which may be tightened for Vthe purpose of binding theplates comprising the stock against the side ofthe blade 3 so as to holdthe blade at any of its numerous adjustments.

In using the, instrument, the blade is angularly adjusted between thespaced portions of the stock so that the scale marks of the severaldiagonal series upon the blade,

may be brought into registration with thatY straight edge of the stockwhich lies at the top of the several columns of numerals which aremarked upon the stock, and which ico iio

have been previously referred to, and it will be understood that thesaid straight edge of either ofthe spaced portions of the stock is to bedisposed against the work and that al pencil or` other markinginstrument is to be drawn along one or the other of the edges of thetriangular portion of the blade.

j substantially the form of a right angle triangle and pvoted at onecorner to the said stock, the side edges of the blade constitutingmarking edges, one face of the blade being provided with a plurality oflines eX- tending parallel to that side edge of thel blade remote fromthe pivotJ and dividing the said face into a series of spaces, the saidface of the blade being provided within each of said spaces with aseries of scale marks designed t0 register With the straight edge 15 ofthe stock When the blade is moved upon its pivot.

In testimony whereof I aliix my signature in presence of two Witnesses.

ALBERT C. ERNEST.

lVitnesses WILLIAM Louis ODELL, WILLIAM M. WELLS.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

